How did oil end up in Alaska?

A couple of years ago, a Republican congressman, Joe Barton, thought he’d “baffled” the US Secretary of Energy, Dr Steven Chu, when he asked him the seemingly simple question “How did all the oil and gas get to Alaska and under the Arctic Ocean?”

Naively thinking that Alaska, and the rest of the United States, has stood for time immemorial in the same place on the globe, it it is reasonable to assume that the congressman was trying to make a point about global warming: namely that in previous ages the Earth was a lot hotter and hence Alaska was a verdent wonderland which contained the necessary materials for the formation of oil and gas.

Such a gross misrepresentation of the science needs to be unpacked.

Firstly, how does oil and gas form? Well, oil and gas are the remains of dead organic matter (primarily microscopic organisms and acquatic plantlife) that have fallen to the bottom of a sea, ocean, or lake, been covered with mud and other sediment. Over the course of millions of years, enough rock accumulates on top of this organic matter that it experiences the right combination of pressure and temperature, and very gradually changes it into oil. We’re talking anything between ten and three hundred million years! Under the right conditions this oil can rise up through semi-permeable rocks, and if its in the right place, end up trapped under a “cap” of non-porous rock. Once here, provided the geology is relatively stable, the oil reserve can remain for millions of years to be found by young, eager oil companies.

Some important points to note: most dead organic matter doesn’t get covered in sediment or mud swiftly enough before microbes and other microorganisms break it down and recycle the material. Under water works well because the lack of oxygen helps preserve the organic matter for longer. On land, buried organic matter such as trees, ferns, and plants, can eventually become coal deposits under the right conditions. Second, the vast majority of oil produced doesn’t normally get trapped under impermeable caps, but leaks to the surface, where it is–in geological timescales–rapidly broken down.

So, the first element of Joe Barton’s incredulity is nonsense. Oil forms from marine organisms. Organisms that might well have been swimming in the “Arctic Ocean” hundreds of millions of years ago, and have gone through the usual process of oil formation. There was no “getting” to Alaska as the congressman puts it.

However, Barton might’ve stumbled on a geological fact, despite seeming to have some level of skepticism to the notion of “continental drift”. 225 million years ago, Earth’s landmass was one giant continent called Pangea. The continents that we see today are the result of this supercontinent breaking apart according to the laws of plate tectonics. Since, oil deposits can form over hundreds of millions of years, it is perfectly possible that Alaskan oil reserves originally came from plant and sea life that lived nowhere near the poles.

Science. Sometimes you need to dig deeper. And remember the Earth is older than you, me, the Republican party, and even the dinosuars.

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